Febrtjakt 18, 1916] 



SCIENCE 



249 



Association and the delegates to the Scientific 

 Congress. 



On Tuesday, January 4, 1916, two sessions of 

 the association were held in the large lecture room 

 of the U. S. National Museum — the first at 10 a.m. 

 and the second at 2 p.m. President Campbell pre- 

 sided. 



Abstracts of the papers presented are aa fol- 

 lows: 



Some Phases of the Origin and Evolution of the 

 South American Fresh-tvater Fishes: Cakl H. 



ElGENMANN. 



The freshwater fish fauna of tropical America 

 is very rich in species. It is entirely distinct from 

 the fauna of Patagonia to the south of it and to 

 the fauna of North America. The fishes of Pata- 

 gonia have their nearest relatives in Australia 

 and New Zealand. The tropical fauna does not 

 extend south of the La Plata basin. In degrees 

 of latitude it extends much further south of the 

 equator than north of it. Northward it has filt- 

 ered into western Colombia and thence through 

 Panama into Central America, Mexico and in rep- 

 resentatives of two genera into the southern 

 United States and Cuba. 



The tropical American fauna has its nearest 

 relatives in Africa, while many of the elements of 

 Africa and South' America may be leftovers from 

 faunas formerly extending over much larger por- 

 tions of the globe, or may have been independently 

 derived from the ocean. The Charaeidse and the 

 Cichlidje seem to demand fresh waters for their 

 migration from place to place. Inasmuch as these 

 families are not found in Europe and evidently 

 only intrusively in the southern United rStates and 

 Mexico they seem to demand the presumption of 

 a former land bridge or land wave connecting 

 South America and Africa. 



Aside from minor expeditions several notable 

 expeditions collected fishes in various parts of 

 South America during the last century. Between 

 1817 and 1820, Spix and Martins collected in east- 

 em Brazil. John Natterer, between 1817 and 

 1835, collected in Brazil from Eio de Janeiro to 

 Cuyaba, down the Guapore and Madeira and in 

 the Rio Negro. In 1843, Castelnau made an ex- 

 tensive journey through South America. All of 

 these expeditions were "Natural History" expe- 

 ditions and devoted as much or more time to 

 other things as they did to fishes. 



In 1865, Louis Agassiz led the Thayer expedi- 

 tion to Brazil and devoted over a year, with 

 numerous assistants, primarily to the collection of 



fishes. During the current century, Mr. John 

 Haseman traveled more extensively than any 

 other expeditions in Brazil, Uruguay, Argentina 

 and Paraguay and devoted himself almost ex- 

 clusively to the fishes. The present speaker col- 

 lected fishes in British Guiana and Colombia while 

 Charles Wilson collected in western Colombia, Mr. 

 Arthur Henn in western Ecuador and Messrs. 

 Meek and Hildebrand in Panama. 



The fish fauna of tropical America consists of 

 many iutrusives from the ocean, like the stingaree, 

 the flounders, the puffer and various sciaenids. 

 Of a few relicts, like Osteoglossus and Lepidosi- 

 ren, of Cichlids, Poecilids and an abundance of 

 catfishes and their relatives, the Loricariidae, and 

 Callihethyidse, etc., and above all, a host of Char- 

 acids which have paralleled, both in habits and in. 

 form, most of the other freshwater fishes of the 

 world. 



Botanical Explorations in South America: Joseph 



Nelson Rose. 



Dr. Rose gave an account of his two exploring 

 trips to South America, the first one being on the 

 west coast, when Peru, Bolivia and Chile were ex- 

 plored, and the second one being on the east coast, 

 in Brazil and Argentina. He called attention to 

 the need for natural history exploration in South 

 America and the unusual opportunities for the 

 carrying on at the present time of this work by 

 naturalists from the United States. He spoke of 

 the kindly feeling shown by the South American 

 scientists, and their willingness to assist him in his 

 work, and of their interest in scientific work gen- 

 erally as carried on by the institutions of this 

 country. 



Mention was made of the interesting biological 

 problems awaiting investigation, and of the fact 

 that many new plants and animals are being 

 found by collectors, and that there is great need 

 of a restudy of the species already described. 



Dr. Rose stated that North American collections, 

 especially of plants, unfortunately contain very 

 poor representations of South American material. 



The various cactus deserts of South America 

 were described, special attention being called to 

 the remarkable display of epiphytic cacti which 

 are to be found in the region of Rio de Janeiro. 



The lecture was illustrated by lantern slides 

 showing the desert and mountain types of vegeta- 

 tion. 



The Distribution of Bird Life in Colombia: A 

 Contribution to a Biological Survey of South 

 America: Frank M. Chapman. 



